In this experiment, an inner transition metal oxide-based nanocomposite of ferrite and antimony heterojunction (LaFeO₃/Sb₂O₃) was fabricated by hydrothermal method for photocatalytic degradation of malachite green (MG) dye under the irradiation of visible light. The fabricated nanocomposite was characterized by various analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR) for functional group analysis, X-ray diffraction (XRD) plan determines the nanocomposite crystalline size the typical crystalline size of around 42 nm was calculated via the Debey -Scherrer method, and Field emission scanning electron microscopy (FE-SEM) determines overall morphology of the composite depicts the random distribution of Sb particles over Ln, which has led to increased reactive sites and probably may result in increased surface area. UV−Vis absorption spectra confirmed an absorption peak at 420 nm in the visible region, and band gap values are found to fall in the range of 2.4 eV. The energy dispersive X-ray (EDAX) analysis confirmed the presence of Ln and Sb in the sample. Moreover, the surface areas of the prepared samples were determined by the electrochemical double-layer capacitance (EDLC) using cyclic voltammetry. Impedance studies demonstrated lower charge transfer resistance for the heterojunction as compared to ferrite and antimony oxide. The photocatalytic activity of the samples was checked for the decolorization of malachite green and it was observed that the composite nanomaterials show maximum response with 95% degradation of MG in a period of 88 minutes. Scavenging experiments established the involvement of hydroxyl radicals (OH˙) in the photodegradation mechanism of malachite green while recycling experiments demonstrated the reliability and long-term use of the catalysts.